The instant invention relates to medical apparatus and procedures, and more particularly to a method and apparatus for controlling the body temperature of a patient.
It has been found that the body temperatures of patients are often significantly reduced during surgical procedures, particularly those which are carried out under anesthesia. This is mainly due to the side effects of most types of anesthesia, although it is also partially a result of the fact that most operating rooms are normally maintained at reduced temperature levels (between 60.degree. F. and 65.degree. F.) in order to prevent surgeons and other operating room personnel from becoming overly warm due to the stresses involved with most surgical procedures. It is also partially due to the fact that most patients are clothed in hospital garments which provide only minimal warmth during surgical procedures. In any event, it has been found that these factors often cooperate to lower the body temperatures of patients undergoing surgical procedures to significantly reduced levels, causing hypothermia, which can have profound deleterious effects on the cardiac, metabolic, hematological and overall physiclogic well being of patients. In this regard, numerous studies have been published demonstrating the deleterious and potentially fatal effects of such post opera-tive hypothermia.
A number of apparatus have been heretofore available for controlling the body temperatures of patients during and after surgical procedures involving general anesthesia. These devices which represent the closest prior art to the subject invention of which the applicant is aware are disclosed in the U.S. patents to HARDY, No. 3,674,034; VOSS; No. 4,867,230; SHAH et al, No. 4,532,414; and, AUGUSTINE et al, No. 4,572,188. Some of these previously available apparatus have included heated covers or blankets which are adapted to be received over the bodies of patients. However, it has been found that covers of this type are frequently cumbersome and impractical for use during surgical procedures. Other previously available devices have included heated pouches which are securable to various strategic areas of the bodies of patients. However, these devices have been found to be somewhat ineffective since they are only operative for heating localized areas of the bodies of patients. Still other previously available devices, such as the one disclosed in the above-mentioned U.S. patent to Shah et al, are operative for controlling the body temperatures of patients by heating I.V. fluids administered to the patients. However, many of these devices have left long sections of I.V. tubes exposed to ambient air after the fluids contained therein have been heated, so that the I.V. fluids are cooled before they reach patients. Accordingly, it has been found that there is a need for a more effective apparatus for controlling the body temperature of a patient by directly heating the body of the patient and/or more effectively heating I.V. fluids before they are administered to the patient.
The instant invention provides an effective method and apparatus for controlling the body temperature of a patient both during and after a surgical procedure, such as one involving general anesthesia. The apparatus of the instant invention comprises a heater for generating a supply of heated air and a flexible patient air hose which is operative for receiving heated air from the heater and positionable on a supporting surface so that it extends along a portion of the perimeter of the body of a patient when the patient is received in a substantially horizontal disposition on the supporting surface. The air hose has a plurality of spaced apertures in the side wall thereof, and accordingly it is operative for dispensing heated air adjacent the body of the patient. The apparatus preferably further comprises a surgical drape which is receivable over the patient air hose and the adjacent portion of the body of the patient for temporarily retaining a portion of the air dispensed from the patient air hose adjacent the patient. In one embodiment of the subject invention, the surgical drape is unattached to the air hose, whereas in a second embodiment the air hose is loosely attached to the underside of the surgical drape so that the air hose and the surgical drape can be assembled on a patient as a unit and then adjusted as needed. The patient air hose is normally constructed so that it is positionable so that it extends along substantially the entire perimeter of the body of the patient, and it preferably comprises an elongated section of corrugated air hose having sequential annular raised and recessed sections in the outer surface thereof. However, it will be understood that the hose is preferably also constructed so that it is adaptable so that it only extends along selected portions of the perimeter of the body of a patient. The apertures in the air hose are preferably located in the recessed sections thereof, and the apparatus preferably further comprises a flexible sleeve which is receivable over a portion of the patient air hose for restricting the outward flow of air from the apertures therein in selected areas, such as those areas where heated air from the air hose might interfere with an operating procedure. The apparatus preferably still further comprises an I.V. heater assembly including a section of elongated flexible I.V. air hose and an elongated section of one or more I.V. tubes received in the air hose so that the I.V. tubes coextend a distance therewith. The I.V. air hose is adapted for receiving heated air from the air heater, so that the heated air is operative for heating the I.V. tubing and an I.V. fluid received therein, whereby the I.V. fluid can be administered to the patient at an elevated temperature level (relative to ambient temperature) for further controlling the body temperature of the patient.
The method of the subject invention, which is operative for controlling the body temperature of a patient, comprises the steps of assembling the patient air hose on a supporting surface, so that the air hose extends along a portion of the perimeter of the body of the patient and feeding heated air to the interior of the air hose, so that at least a portion of the heated air is dispensed through the apertures adjacent the body of the patient. The air is preferably dispensed substantially uniformly around the body of the patient, and the method preferably further comprises applying a surgical drape over the air hose and the adjacent portion of the body of the patient, and it preferably still further comprises feeding heated air to an I.V. heater hose surrounding an I.V. tube in order to heat an I.V. fluid in the I.V. tube before the I.V. fluid is administered to the patient.
It has been found that the method and apparatus of the subject invention can be effectively utilized for controlling the body temperature of a patient both during and after a surgical procedure involving general anesthesia. In this regard, it has been found that by dispensing heated air from an air hose which is assembled so that it extends along the perimeter of the body of a patient, it is possible to effectively maintain the body temperature of the patient at a normal level, despite the effects of anesthesia. It has been further found that it is possible to even more effectively control the body temperature of a patient when a surgical drape is applied to the patient so that the surgical drape extends over the air hose and the adjacent portion of the body of the patient ill order to maintain heated air which is dispensed from the air hose in close contact with the body of the patient. Even still further, it has been found that by heating an I.V. fluid which is administered to a patient by passing an I.V. tube containing the I.V. fluid through an elongated I.V. air hose which coextends a distance with the I.V. tube and which preferably terminates adjacent the patient, it is possible to effectively further control the body temperature of the patient.
Accordingly, it is a primary object of the instant invention to provide an effective apparatus for controlling the body temperature of a patient.
Another object of the instant invention is to provide an effective apparatus for controlling the body temperature of a patient by exhausting heated air along the perimeter of the body of the patient.
Another object of the instant invention is to provide an effective method for controlling the body temperature of a patient by dispensing heated air along the perimeter of the body of the patient.
An even still further object of the instant invention is to provide an effective method and apparatus for controlling the body temperature of a patient by heating an I.V. fluid before it is administered to the patient.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.